The disclosure generally relates to toys for use in water, and more particularly to hydrodynamic toys adapted to be launched for self-propelled travel through an underwater trajectory.
Aerodynamic toys capable of being hand-launched through the air have been known for many years, and include balls, flying discs, boomerangs, toy gliders, etc. Aerodynamic toys typically are characterized by a combination of properties allowing a user to launch the toy into the air by hand so that the toy travels a substantial distance through the air along a trajectory selected by the user. Specifically, each of these toys has a size and shape that, in relation to the weight of the toy, enables an average user to apply a launching momentum sufficient to overcome, at least temporarily, the forces of gravity and wind-drag on the toy. Some aerodynamic toys are also configured to create lift when launched through the air to increase the distance the toys travel before descending to the ground.
While hand-launchable, aerodynamic toys are well-suited for use in air, they are not well-suited for use underwater. For example, objects traveling through water experience a significantly higher amount of drag than do objects traveling through air, because water has a much higher density than air. Similarly, objects experience greater buoyancy in water than in air due to the higher specific gravity of water than air. For these reasons, toys intended for use underwater should employ hydrodynamic rather than aerodynamic values and thus, typically will have different combinations of size, shape, and weight, than those intended for use in air. In U.S. Pat. Nos. 5,514,023 and 6,699,091, the disclosures of which are hereby incorporated by reference, various hand-launchable projectile toys are disclosed that are hydrodynamically configured to travel substantial distances underwater. The toys include elongate, contoured bodies that include fins or other trajectory-stabilizing structures that project from the tail section of the body. In some embodiments, the trajectory-stabilizing structure is adapted to impart a righting moment to the toy during underwater travel, while in others the structure is adapted to impart a steering moment to the toy during underwater travel.
These underwater toys are adapted to be hand-launched through a pool or other body of water, with the particular configuration, construction, and/or buoyancy of the toy affecting its hydrodynamic path through the body of water. The hand-launchable size and geometry of the toys enable them to be grasped in a user's hand, such as in the notch formed by the user's thumb and index finger, and manually propelled through the body of water. However, some users may lack sufficient strength, size and/or coordination to effectively launch these toys along a suitable underwater path through the body of water. Others simply may desire an underwater toy that does not require manual propulsion through the body of water.